It's also somewhat problematic: the above poster made a lot of assumptions about work day, but they're less and less true. Empty nesters, people without kids ye

It's also somewhat problematic: the above poster made a lot of assumptions about work day, but they're less and less true. Empty nesters, people without kids yet, childfree folks, all that rules out the school schedule (looking at the size of the school in my town, it's a small minority of people who have school aged childrens). Then the 9-5 work day. Tradefolks often start much earlier. People working late shifts at restaurants and other service industries are very unlikely to do simple 9-5. People in tech are all over the place. "Early bird gets the worm" because if you're not at the default or earlier, you're basically fucked: hope you didn't need to sleep 7+ hours after that night shift, because you certainly aren't going to when the neighbors let the dog out to bark!